A Human Heart
by TheWeirdThang
Summary: Marceline has reunited with Princess Bubblegum after a fight. But how does Finn feels about this? Either way, Marceline has experienced first hand what can happen when you play with a human heart and she does not want to relive it.
1. Chapter 1

**A.N: I've seen a lot of fanfictions around about these two and I've never seen any in depth feelings on Finn's side. So I decided to write an extreme case for Finn's side of the story. Before you read, I'd just like to let you know I'm pretty for Bubbline (I think that's right) and this story is in no way against it. Just like to make some drama. Anyway, onto a nice little intro.**

She stood there, speechless.

Not often Marceline, the Vampire Queen has been described as speechless. Heck, no one has said that for over five hundred years. She always had something to say. Whether or not it was full of rage, sadness or just laughter, Marceline always had one little quip under her sleeve. But this time, she was rendered completely speechless.

It was a full moon. It did something strange but yet enticing to her pink hair.

Bonnibel was sitting next to a pond in her royal garden, unaware of her night watcher (a more polite term for stalker). She was staring into the pond, the reflection of the full moon making her eyes sparkle, her face glow. Marceline wouldn't care if the globbing Lich came along and ate the town. Nothing could take her eyes off the sight which turned her heart guts into goo.

Bonnibel sighed deeply, stood up and turned towards Marceline much to her horror "_No, no, no! Stay like that! Oh glob, what is she going to think?!" _Marceline wracked her brain for any excuse why she was standing not five meters away from Bonnibel, saying not a single word and watching her for the past freaking half an hour.

Bonnibel suddenly stopped as her she saw Marceline, her eyes widening. A deep red tinged plagued Marceline's cheeks. The two of them stood like that for what seemed an eternity but turned out to only be a few seconds. The bubblegum princess broke it with a sudden outburst,

"What the dang Marceline?! You gave me such a fright! What are you doing standing there?" Her little arms were waving around.

"_She looks surprisingly cute being flustered"_ Marceline shook her head, trying to physically get rid of the thoughts encroaching on her mind to no avail "I-I…er was just trying to er…scare you! Yeah! Wooooooo scary!" Marceline waved her hands around in a 'creepy' manner. Her blush deepened as she felt like a dweeb.

"Can it Marceline. What are you really here for? You stopped those sort of games long ago…" Bonnibel looked to the side, old nostalgic memories entering her head _"No, I am the princess of this land and I will act like one!"_ With that thought, her eyes grew determined and she stared angrily once more at Marceline.

"Anyway you can't just enter here, stare at me for glob knows how long waiting to say something and just blow it off like that. You aren't that sort of person Marceline!"

Marceline stood there, stuttering and trying to get some excuse out. She looked down, shutting up and blushed madly. She had no idea why she was just staring at her! She even had forgotten why she came here in the first place. Glob what was the reason?

"_Finn…Finn wanted me to talk to her. That's right. He wanted some help with the ladies and asked me to make him seem better to PB. Why is he so dumb? Why can't he just talk to her himself?"_ She looked up again, staring at the enraged goddess that stood before her _"Ah, that's why. Okay, okay. Just do what Finn asked. Chat her up for him."_

"Your hair looks beautiful in the moonlight." Ahhh cram baskets.

"I… eh what?!" Bonnibel put her hand on her chest, mouth open with a light blush spreading across her cheeks. Darn it, she was supposed to talk Finn up to the princess, not talk the princess up for Finn!

"I meant that your eyes and your face looks gorgeous off the reflection of the pond!" Glob darn it, shut up Marceline!

"Marceline! Quit joking around! That is very inappropriate!" The blush grew on Bonnibel's cheek, though unbeknownst to Marceline who was currently punching herself in the gut. _"Why can't I shut up?! What the heck am I feeling? She must think of me as a total weirdo right now!" _She did.

"I'm sorry Bonnie," PB winced at her nickname, more memories flooding into her mind "I was supposed to come here to chat you up for F-"

"You what?!" A sudden outburst came from the princess who now was red as a tomato "Marceline we aren't like that anymore!"

"Wah? No I'm not talking about that, I'm talking about F-"

"No Marceline! I'm not hearing anymore of this. You know why I couldn't…why we can no longer be what we were." Her voice grew smaller and more quite as she talked.

"Argh! Would you just listen! I'm talking about Finn here! The little dweeb wanted me to talk you up about him and find out how you felt about him. Jeez you always jumped to conclusions" Marceline dragged a hand down her face in exasperation _"Glob, what have I gotten myself into…"_

"Me? I jumped to conclusions?! I happen to remember that one certain vampire thought I was kahoofing with another guy in the daylight when he was an ambassador from the jungle kingdom!" She took a step forward, finger pointing angrily at the Queen of Darkness.

"Hey! We found out that he had other thoughts in mind other than 'keeping the peace'. He thought sealing the treaty was a good ol' smooch!" Marceline screamed, swiping the air angrily and advanced on the pink fury.

"Yeah but the kahoofing was all on his side! I didn't want any part of it. How about the time where the Ice King stole me for the first time huh? You thought I wanted to become happily married or something and teared the whole place apart, screaming at me the whole time like I was the one who kidnapped him!" She took another little raged filled step forward, flicking her hair backwards.

"_Jeez she's beautiful…"_ "We both know I had complicated past with Simon and there were other emotions mixed in and this was shortly after that ambassador episode. What was I supposed to think? You didn't show any signs of struggle!" Oh glob she was going to get it and Marceline matched Bonnie and took a step towards her.

"I didn't know he was bat jack crazy! I thought I could help him or something because he was so lonely so I went with him. How was I supposed to know that he was insane and would do that to me?" One more step closer.

"He doesn't mean too! He's a good man. It's that damn crown on his head and taking it off for a long period of time will surely kill him. I can…I can still save him!" Marceline took another step forward, her hot angry breath blowing on PB's face.

Wait…what?

Sure enough the steps both the royalties took brought them inside each other's reach, faces only a few inches apart. The anger shared between the two melted away suddenly and they stared into each other's eyes. Only tension remained, strung out like a violin. Marceline tried to calm her breathing down as she felt it picking up pace. What was she feeling? Why was she feeling like this? They were over, they clearly ended it. Well she clearly ended it. But her reasoning never seemed enough to satisfy her long dead heart.

"Bonnie, what happened to us?" The question escaped Marceline's mouth before she could stop it. A wave of feelings coursed through her body. Horror, shame, fragility, guilt, anticipation, excitement and even a little bit of hope.

Bonnibel's head back recoiled as if Marceline slapped her across the face, eyes widening the same as dinner plates. She began to stutter,

"I-I-I t-told you didn't I? My kingdom needs me. I can't betray them, I can't let them go. They need me, glob they're so helpless! Simply being scared makes them explode Marceline! I need to be there for them." Her voice grew more confident as she took comfort in her role. Anger and betrayal ripped through Marceline again, her face turning into a snarl.

"What about me Bonnie? What about what I want huh? I have lost everything! Everything to someone or something's whim without them consulting me, asking how I felt. I thought you were different Bonnie. I thought you were something else." Tear's threatened to fall from Marceline's eyes and she wiped them viciously _"I'm not letting her take these away from me as well."_

"I know this is harsh Marceline, but you are only one person. My kingdom contains over a thousand subjects and each one needs me to help and support them! If I had a relationship with you, my people will suffer. I'm…I'm not old enough yet. I can't do it Marceline. Not yet". The princess hung her head in defeat and a sob shook her whole body.

It was too much for Marceline. She wasn't use to this sort of display of emotions. She is so used to bottling them up inside and isolating herself from everyone so that she wouldn't have to deal with these emotions. But now it was like, emotion city population Marceline and Bonnibel. She couldn't escape it. Now she saw the princess that was so important to her, chewing herself up because of the feelings that she brought up.

"Bonnie, you keep doing what your people want. I see yourself slaving away, working yourself until you collapse to satisfy them. Your nerdy, sciency stuff takes too much of your time. You're so smart but yet so dumb by working yourself so hard. Your people know how much you work, they wouldn't mind if you slack off now and again. Think for yourself for once Bonnie. I do all the time." She added with a small smile which drew out a small giggle from her princess _"My princess?"_

"Give me another go Bonnie. Please. Don't be afraid, your people can take care of themselves for a short amount of time and they'll understand. Plus, you're getting boring," on this note Marceline picked Bonnibel up and flew into the air, "I think you could use a little living up." She grinned, her fang poking out.

Bonnie yelped and gave a sharp look before squirming around Marceline's hold to get comfortable. She sighed at her vampire friend and then looked away from her.

"I don't know Marceline. It was so hard last time. I broke down so many times. I-I just don't know. I care for you. Being around you make my heart guts beat furiously," she blushed hard at her little confession "but letting go of my responsibility as princess seems so…rash".

"Pfft hahaha, oh Bonnie. Just because you will be going out with me doesn't mean you won't be taking care of your people. You think your mum and dad didn't do anything? You can do it and I'll help you. I have been a queen for a thousand years!" She replied with that same old quirky smile she has.

Bonnie simply rolled her eyes "Yeah, the queen of the most chaotic realm! You don't have to do anything at all! You just go there and show off your muscles!" Marceline quirked an eyebrow,

"Oh, you've noticed my muscles?" She responded huskily, bringing a deep red hue to the princess's cheeks who began to squirm in the vampire's arms. Marceline burst into laughter again, feeling the rare happiness that she is feeling now.

"Oh Bonnie, you are so easy." She managed to choke out between gasps. The princess glared at her as if her eyes were the sun and if she'd stare hard enough, Marceline would burn to a crisp. Marceline calmed down and a small smile went across her face as she held the beautiful person that was in her arms. She wished this moment could go on forever.

"So Bonnie, want to give me another go?" She asked softly. Princess Bubblegum stared up at the vampire, the moonlight giving her a glow as if she was more alive than anything in the whole land of Ooo.

"Yeah, yeah why not." She turned to her kingdom "And you better accept it you butts!" Marceline and Bonnibel giggled together.

"O-Okay!" Came the reply of Cinnamon buns who was unfortunately watching the whole ordeal. Princess Bubblegum's face turned pale white but Marceline's giggle turned into a full blown laugh and she had to put the princess down before she dropped her.

"Shut up Marceline! I didn't know anyone would be listening in!" She stood over the Vampire Queen who was now showing very unroyal behaviour rolling on the gross, snorting and pointing at the princess.

"You-hahaha-you should see your face. Oh glob it's hilarious!"

"I said can it Marceline!" Bonnibel cried, dragging her hands down her face in an attempt to change the oh-so-hilarious face that she was now exhibiting. Embarrassment coursed through her veins like poison and she fumed on the spot. Marceline after snorting a few times managed to sit up and wipe a tear from her eye. _"I've never felt so happy before. Jeez, this girl is so lumping good. Why didn't I realise this sooner?" _

"You know I wasn't being serious Bonnie. And you know that dummy, he'd forget all about it within a half an hour. Just don't worry and calm down or you'll explode." She put further emphasis on the explode by simulating an explosions with her arms which Bonnie rolled her eyes for what it seemed like the hundredth time. She took a big breath in and let all the complicated emotions and fear out.

"Yeah you're right Marceline. And anyway, I'm sure that Finn would be more than willing to help if I'm in any sort of strife."

All the colour (which wasn't much) drained from Marceline's face.

Oh crud.

Finn.

**A.N: The next chapter will be Marceline's confession to Finn. So I hoped you enjoy it and criticism is welcomed. Anyway, thanks for reading. **


	2. Chapter 2

**A.N: Someone asked where this story was heading so I thought to give a small brief. It's mainly going to deal with Marceline and Finn and their sudden destruction of friendship. Not too much romance, you just witnessed probably the majority of it. There isn't any FinnxMarceline, sorry the tags must of confused people. And I'm actually more of a fan of FinnxMarceline myself but I just can't think of a story for them too.**

**There is going to be quite a bit of action as well so if you aren't into that sort of thing then you probably shouldn't read. Oh and Finn is going to turn dark.**

**Probably should of mentioned that in the summary. Anyhow, enjoy.**

Oh crud.

Finn.

How could she forget about him? Oh glob, he sent her here so she can get closer to Bonnibel. Not so she can reunite old love with her! What is he going to think? She betrayed him, she's sure of that. She knew he liked Bonnie a lot and then she just goes right ahead and steals her. Maybe she can go back against her word. She looks up at Bonnie, mouth open to sp-_ "I can't do it! Look at her! She's so lumping good and she's MINE!"_

So ending it with her and getting her to like Finn was off the list of things. But what is she going to do? She didn't want to lose Finn. She doesn't actually think he's a total dweeb but a real cool friend and she didn't want to lose that. Gargh she sucks at emotions!

"Marceline, are you okay? You haven't spoken in a bit and you're pale…well paler than usual." Bonnie giggled at her little joke, not taking any real notice of the internal conflict which her now girlfriend was going through. Who could blame her? She was emotionally unattached as a stick sometimes.

"I just *sigh*, it's Finn. He likes you Bonnie, a lot and I was here to like, make him seem like he was not a total weenie."

"But why? I know he isn't a total weenie but the courageous hero of Ooo who has saved me and my kingdom's butt so many times." Bonnie stated, giving off the damsel in distress sort of vibe which brought little aches of jealousy through Marceline _"Why can't I be her hero?"_ She shook off the creeping thoughts of doubt in her head and did a dramatic sigh.

"Glob you're so stupid. Finn likes you Bonnie and he wants to seem better for you since you keep blowing him off. And now instead of that, I've gone and snapped you out of his reach! What will he think of me?" Marceline ran her hand through her hair irritably, trapped in a situation which she can't get out of. Bonnie just smiled at the vampire, took two steps and kissed her on the cheek. Marceline blushed madly and touched where she kissed.

"W-wah?! What the heck Bonnie," she took a step back "why'd you do that?"

"Because Marceline, you're also so stupid sometimes. It's Finn. Just explain it to him and his kind heart will forgive you surely. He is Ooo's hero after all." The princess smiled reassuringly at the shocked vampire, placing a hand upon her shoulder,

"Go, go talk to him Marceline. Everything will be fine." She then promptly delivered another kiss on Marceline's cheekwhich the vampire took more gracefully this time…barely. The Queen of Darkness looked up at her girlfriend with fear and desperation in her eyes. But seeing that steady strength in Bonnie renewed her confidence once more.

"Yeah, you're right Bonnie. It's the little weenie that we all know and love. Heh, what the worse can happen?" Famous last words. Marceline hugged Bonnie sort of awkwardly but it was warming for the both of them none the less. She then flew off and gave a farewell wave to her princess and flew towards her house where Finn was planning to meet up with her. The night was colder, more biting to Marceline than usual and she was the lumping Queen of Darkness! She looked up at the full moon and reminded herself of Bonnie and just what happened. It seemed so unreal but yet, she was sure it happened.

"Haha alright! Bonnie is back with me!" Marceline wooped, doing spins in the air as she could not contain her happiness. It has been such a long time since she felt so globbing good and she didn't care if anyone saw her. Well, all except Finn. That thought quickly sobered her up and she flew to her house sluggishly, dreading what she had to do.

"_Okay, okay. So eh, hey Finn! How is it going. I've got some bad news…no, no, no. Hey dweeb, Bonnie is all mine now! No that's even worse! How the heck am I supposed to talk to him. Sigh do I have to apologize and stuff? Totally will ruin my rep but…he's my friend. My best friend. He deserves the truth. Nothing sugar coated (heh sugar coated). I'm sure if I told him my feelings…he'd understand. I hope."_

She could see her cave now, coming closer and closer. Cold beads of sweat went down her neck and she gulped back her anxiety _"Maybe I can swing around back, hide out for a couple of days and maybe he'd forget?"_ This small glimmer of hope disappeared as she saw the young human boy at the mouth of the cave, waving hysterically at her,

"Hey! Hey Marceline! Over here! What did she say? Hey Marceline!" Shouted Finn, now jumping up and down in anticipation and excitement _"Hooo boy, this is gonna be tough."_ She landed next to the boy who was now jumping up and down so much that Marceline had to put a hand on his head and push him down to make him stop. A smirk came across her face _"Or maybe not"_,

"Heh come on weenie, we'll get inside and talk there."

"But Marceline!" Whined Finn like a 5 year old child and the Vampire Queen simply rolled her eyes.

"Get inside dweeb or I'll make ya!" Her face contorted into pure horror, razor sharp teeth and blood red eyes hissed in Finn's face. The boy hero was unfazed by the face which sprung fear into millions of people over the years and ran to the door excitedly. He opened it quickly and waved Marceline in hurriedly, overly nervous for the news. Marceline felt sorry for him and a pang of guilt ran through her body _"Oh you poor, lonely boy". _She stepped inside her home and took a profile of the him.

He was around 14 and the world was harsh on him although he wouldn't complain. His face was filled with boyish charm, a large uneasy grin across his face with bright blue eyes and cheeks which still had traces of baby fat. Small tuffs of golden blonde hair sprang from his white bear hat and it was fairly wavy. The boy was wiry, his arms skinny but taut with muscles. Hence why he was able to wave a sword around as if it were a pencil. His shoulders were beginning to broaden but only slightly. His body, like his arms were skinny and she couldn't tell if his body contained any fat or not. His legs were chicken legs, with a layer of fat covering them. He was only a little over 5'6. Jeez he was a wonderful kid. He wore what he usually wore, blue shirt and deeper blue shorts with his trusty backpack and a sword which was sheathed behind his back.

"So Marceline, what she say? Does she like me because that would be like totally rad but if she didn't that would be cool. Did you make me out like heroic and stuff who is like super smart and mature? Or, or…" Finn projectile vomited words like that for the next minute, each sentence bringing more anxiety and dread to the Vampire Queen. She finally raised her hand to stop Finn talking who suddenly halted midway of saying "Did you mention my pink tuff of her hai-"

"Eh Finn, I've got something to tell you." The boy looked up at her, eyes glimmering with hope and nervousness. He looked so innocent and pure and she was going to crush him _"But he deserves the truth, oh glob, he deserves it so much."_

"Well eh you see Finn, me and eh Marceline had a bit of a past you know. And eh I went up to her and stuff and we sort of argued and things. And then we were, you know very close and we talked some more and thenwegotbacktogetherandImve rysorryforbetrayingyou!" She said the last part in a rush, however the human boy was used to rushed explanations from his brother and picked up every word of it.

"You…what?!" The boy took a step back from the vampire queen, horrified from what he was hearing. He bent down and grasped his head "No, no this can't be happening!"

"_Oh glob, why am I so lumping stupid. He's breaking apart."_ Guilt and pity that was so powerful came after wave after wave through Marceline, almost driving her to her knees.

"I'm so sorry Finn. I know how much you liked her and everything but when I saw her it made my heart guts throb and I just had to have her to myself. I'm so selfish and I'm sorry for hurting you so lumping much but you have to believe me it wasn't out of spite!" She begged, trying to knock some sense into the boy who tore his hat into two, letting his blonde hair fall onto his shoulders.

"How could you do this to me Marceline?! You knew I liked her a lot and you just went ahead and handed my guts on a platter to me. And…and how could PB do this to me? She must of known I had feelings for her…I worked so hard for her and this is how she repays me?!" The boy screamed, never feeling so alone and betrayed as he has now. This turned into fury and the kicked over the hard-as-steel couch over and screamed.

Marceline could see it all now in her mind's eye. What was going to happen because of her mistake. She saw Finn, the hero of Ooo, broken and destroyed because of his betrayal by his love and one of his best friends. She could see that he becomes so wrapped up by it, all he can seek is revenge on those who had forsaken him. He became the villain of Ooo, no longer protecting the weak and allowing predators and him to torment the ones he once protected. She saw him, advancing on Princess Bubblegum in broad daylight where she couldn't help her, sword in hand ready to strike down the one who caused him such pain. Then she saw the despair across his own face as he realised he had done a terrible mistake and took out his self-hatred on the rest of Ooo.

She couldn't allow that to happen. She knew what happened when you messed with a human heart, the sheer destruction it could wrought upon a world. It happened once…over a thousand years ago. She had to rectify her mistake, to stop the creation of a monster that would rip Ooo apart.

A monster…?

The idea hit her like a punch. She knew what she could do. It could save Ooo but it would indeed destroy her friendship with the human boy. She looked up at Finn, who was staring angrily at her with hatred oozing out of his body _"Well, not much to lose anymore"_. She hoped to glob it would work. She bent down and let the most evil cackle she could muster to wrack her body,

"Hahahaha oh Finn you insolent human. All of it is a lie. I can't contain it anymore; it's so hilarious seeing you like that. Yes, I enthralled Princess Bubblegum and made her my slave so she can do as I bid. She is mine and you can never have her!" She swiped the air, giving her most inhuman smile to the boy who just stared at her with shock. He slowly snapped out of it and a snarl went across his face and hope came into his eyes,

"How could you Marceline! How could betray me like this and hurt PB!? What made you do this huh?! You were totally a rad dame and then you betrayed us all! You betrayed me!" The boy screamed in hatred and pain, hot angry tears pouring down his face._ "Oh Finn…I'm going to miss you" _sadness came across Marceline's face for a second before she quickly renewed her act.

"Because I was bored Finny boy! There was too much peace and happiness and I needed some fun. And behold," she gestured to Finn with a swoop of her hand "my fun. Always coming to me, needing help with his love life. Always sharing me his secrets and what's closest to him. So I thought to play a bit of a trick to create drama and terror." She cackled evily again, leaving Finn fuming and crying on the spot _"I'm sorry Finn"._

He wiped the tears angrily from his eyes and took a deep breath in. He then glared at Marceline with raw pain and hatred and he bellowed "Marceline! For the Land of Ooo and for betraying your friends…" he grasped the handle of his sword. _"Oh no, no, no oh glob Finn NO!"_ Marceline screamed in her mind, wishing she hadn't said anything.

"I will destroy you so that Princess Bubblegum will be released from her curse…and so she can be rightfully with me." The horrible sound of rasping steel came forth as he unsheathed his weapon and held it out before him, his snarl disgusting and promised only pain. _"This isn't supposed to happen, no! You were supposed to try and reason with me, oh glob Finn don't!"_

He let out a battle roar filled with the promise of death and he leapt forward, swinging his sword down with all his might. Marceline managed to barely dodge the attack which would have split her down the middle if she didn't side stepped.

"_Oh Finn, what have I done?"_

**A.N: Okay the next chapter is going to be quite actiony, so don't watch if you don't like. I hope you enjoyed this chapter and I'm sure to write another one (probably not at the same speed though). Anyway, thank you for reading.**


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